• Issue

    Tectonics: Volume 39, Issue 4

    April 2020
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Issue Information

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Issue Information

  • First Published: 27 April 2020

Comments

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Comment on “The Mesozoic Margin of the Maghrebian Tethys in the Rif Belt (Morocco): Evidence for Polyphase Rifting and Related Magmatic Activity” by Gimeno-Vives et al.

A. Michard,  O. Saddiqi,  A. Chalouan,  M.C. Chabou,  P. Lach,  P. Rossi,  H. Bertrand,  N. Youbi, 
  • First Published: 15 March 2020
Key Points

  • The main Mesorif gabbros emplaced in a Liassic oceanic domain and do not belong to the Central Atlantic Magmatic Province (CAMP)
  • CAMP dolerites may occur separately next to the oceanic gabbros in the structurally complex Mesorif zone
  • The prerift/synrift cover of the distal margin could have emplaced by gravity sliding onto the Mesorif oceanic crust

Research Articles

Open Access

Controls on Continental Strain Partitioning Above an Oblique Subduction Zone, Northern Andes

J. M. Schütt,  D. M. Whipp, 
  • First Published: 18 March 2020
Key Points

  • Factors influencing formation of continental slivers investigated using 3-D numerical models of finite-width oblique subduction systems
  • Model results indicate that convergence obliquity and the presence of weak zones in the upper plate are key to formation of well-defined slivers
  • Model predictions are in good agreement with geodetic observations of sliver motion in the Northern Volcanic Zone of the Andes

Free Access

Large Earthquakes Driven by Fluid Overpressure: The Apennines Normal Faulting System Case

C. Chiarabba,  M. Buttinelli,  M. Cattaneo,  P. De Gori, 
  • First Published: 05 March 2020
Key Points

  • The complex and diffuse fault segmentation of fault system derives from intense preexisting crustal heterogeneity
  • Large-magnitude earthquakes along the system are related to broad high Vp/Vs overpressurized volumes at the base of the seismogenic layer
  • Monitoring of this target will help decipher the interaction between deep fluids and seismicity before and during major seismic sequences

Free Access

Mesozoic-Cenozoic Regional Stress Field Evolution in Svalbard

Harmon Maher,  Kim Senger,  Alvar Braathen,  Mark Joseph Mulrooney,  Aleksandra Smyrak-Sikora,  Per Terje Osmundsen,  Kei Ogata, 
  • First Published: 06 March 2020
Key Points

  • Syn-sedimentary Triassic normal faulting in eastern Svalbard suggests the maximum horizontal stress was oriented NW-SE to WNW-ESE
  • A Cretaceous regional jointing episode occurred in Svalbard with the maximum horizontal stress oriented approximately E-W
  • Svalbard stresses changed as plate activity shifted from the Urals (to E) to the Amerasian Basin (to N) to the Atlantic transform (to W)

Open Access

Subduction Reversal in a Divergent Double Subduction Zone Drives the Exhumation of Southern Qiangtang Blueschist-Bearing Mélange, Central Tibet

D. Li,  G. H. Wang,  P. D. Bons,  Z. B. Zhao,  J. X. Du,  S. L. Wang,  G. L. Yuan,  X. Liang,  L. Zhang,  C. Li,  D. R. Fang,  Y. Tang,  Y. L. Hu,  Y. Z. Fu, 
  • First Published: 17 March 2020
Key Points

  • Central Qiangtang HP-bearing mélange formed by short-lived southward subduction in a divergent double subduction setting
  • Progressive inversed shearing exhumed HP rocks
  • Subduction reversal in a divergent double subduction zone can exhume HP rocks through direct slab movement

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Deformational Temperatures Across the Lesser Himalayan Sequence in Eastern Bhutan and Their Implications for the Deformation History of the Main Central Thrust

Djordje Grujic,  Kyle T. Ashley,  Matthew A. Coble,  Isabelle Coutand,  Dawn A. Kellett,  Kyle P. Larson,  David M. Whipp Jr.,  Min Gao,  Nicholas Whynot, 
  • First Published: 06 March 2020
Key Points

  • Crustal-scale shear zones produce inverted temperature fields with transient gradients
  • Each thermochronologic and thermobarometric method registers a different stage of such a temperature field
  • Numerical modeling of multiple thermochronological data sets permits more detailed and accurate reconstruction of the thermal history of crustal-scale shear zones

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Tectonic Evolution of the Northern Oman Mountains, Part of the Strait of Hormuz Syntaxis: New Structural and Paleothermal Analyses and U-Pb Dating of Synkinematic Calcite

E. Carminati,  L. Aldega,  L. Smeraglia,  A. Scharf,  F. Mattern,  R. Albert,  A. Gerdes, 
  • First Published: 12 March 2020
Key Points

  • Musandam faults display multiple kinematics acquired between 74 and 13 Ma
  • Mixed layers illite-smectite paleothermometers indicate deep diagenetic conditions
  • Levels of thermal maturity were acquired during the Late Cretaceous obduction

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Cenozoic Exhumation of the Qilian Shan in the Northeastern Tibetan Plateau: Evidence From Low-Temperature Thermochronology

Weitao Wang,  Dewen Zheng,  Chaopeng Li,  Ying Wang,  Zhuqi Zhang,  Jianzhang Pang,  Yang Wang,  Jingxing Yu,  Yizhou Wang,  Wenjun Zheng,  Huiping Zhang,  Peizhen Zhang, 
  • First Published: 13 March 2020
Key Points

  • Cooling ages and thermal history modeling show increased exhumation of the eastern Qilian Shan at ~15 Ma and ~5 Ma
  • The middle Miocene rapid exhumation indicates expansion of the Qilian Shan driven by thrust fault systems
  • The fast Pliocene exhumation may have been related to left-lateral motion on the Haiyuan fault during the late stage of orogenic development

Free Access

Revision of the Chinese Altai-East Junggar Terrane Accretion Model Based on Geophysical and Geological Constraints

Alexandra Guy,  Karel Schulmann,  Igor Soejono,  Wenjiao Xiao, 
  • First Published: 17 March 2020
Key Points

  • The Chinese Altai and East Junggar are revised using the potential field, geological, and geochemical data
  • Geophysical domains result from the Devonian and Permian tectonometamorphic and magmatic reworking
  • No prominent deep-seated discontinuity defines the Erqis Zone challenging its tectonic importance

Open Access

The 3D Seismic Azimuthal Anisotropies and Velocities in the Eastern Tibetan Plateau Extracted by an Azimuth-Dependent Dispersion Curve Inversion Method

Chuntao Liang,  Zhiqiang Liu,  Qian Hua,  Liang Wang,  Ningbo Jiang,  Jing Wu, 
  • First Published: 18 March 2020
Key Points

  • An azimuth-dependent dispersion curve inversion (ADDCI) method to find the 3D anisotropy and velocity model for the eastern Tibetan Plateau and the western Yangtze Craton; fast propagation directions and magnitudes of anisotropies show strong variations in depth and between different blocks
  • The fastest propagation directions of seismic waves are positively correlated with the GPS velocity directions and the strikes of regional faults in most of the blocks
  • Velocities, magnitudes, and the fast propagation directions of anisotropies show strong block characteristics. This is consistent with the pure shearing model that involves lateral block extrusion and folding and thrusting in the upper crust

Free Access

Evidence for Late Quaternary Deformation Along Crowleys Ridge, New Madrid Seismic Zone

Jessica A. Thompson Jobe,  Ryan D. Gold,  Richard W. Briggs,  Robert A. Williams,  William J. Stephenson,  Jaime E. Delano,  Anjana Shah,  Burke Minsley, 
  • First Published: 06 March 2020
Key Points

  • Less than 5-m high scarps mapped along the margins of Crowleys Ridge on lidar offset <56 ka surfaces
  • Subsurface geophysical imaging reveals offset Quaternary units along the margin of southern Crowleys Ridge
  • Southern Crowleys Ridge is interpreted as a step over in the right-lateral Reelfoot Rift system

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Strain Partitioning and Exhumation in Oblique Taiwan Collision: Role of Rift Architecture and Plate Kinematics

Clément Conand,  Frédéric Mouthereau,  Jérome Ganne,  Andrew Tien-Shun Lin,  Abdeltif Lahfid,  Maxime Daudet,  Lucas Mesalles,  Slawek Giletycz,  Marta Bonzani, 
  • First Published: 12 March 2020
Key Points

  • Strain distribution in south central Taiwan reveals partitioning between orthogonal contraction and left-lateral shear
  • Dome-like architecture and exhumation of high-grade rocks in eastern Taiwan are best explained by transcurrent deformation
  • Oblique convergence and rift architecture accounts for the 3-D strain distribution in Taiwan

Free Access

Detrital Thermochronology Reveals Major Middle Miocene Exhumation of the Eastern Flank ofthe Andes That Predates the PampeanFlat Slab (33°–33.5°S)

A. C. Lossada,  G. D. Hoke,  L. B. Giambiagi,  P. G. Fitzgerald,  J. F. Mescua,  J. Suriano,  A. Aguilar, 
  • First Published: 13 March 2020
Key Points

  • Modern river sand thermochronometry constrains timing of exhumation of the Andes in the flat to normal subduction transition
  • Main exhumation of Frontal Cordillera in this region occurred at 15.3–17 Ma, prior to the onset of flat-slab conditions
  • Timing of exhumation is consistent with an eastward progression of deformation

Replies

Free Access

Reply to comment by Michard et al. on “The Mesozoic Margin of the Maghrebian Tethys in the Rif Belt (Morocco): Evidence for Polyphase Rifting and Related Magmatic Activity”

Oriol Gimeno-Vives,  Geoffroy Mohn,  Valérie Bosse,  Faouziya Haissen,  Mohamed Najib Zaghloul,  Achraf Atouabat,  Dominique Frizon de Lamotte, 
  • First Published: 15 March 2020
Key Points

  • Opening of the Maghrebian Tethys during a major Middle Jurassic rifting phase
  • Late Triassic to Early Jurassic CAMP-related magmatism
  • Non-oceanic nature of the Mesorif Gabbroic Complex and absence of an overlaying oceanic sequence